Solution To Moving A Massive TBM To Location - continued
A piece of the tunnel boring machine is lowered by a Terex AC700 crane.
When completed, the fully assembled tunnel boring machine will be 22 ft (6.96 m) in diameter and weigh 461 ton in total. The new subway tunnel will be almost 2,000 ft (600 m) in length, connecting two areas of the city currently separated by water.
Robert Young, director of operations at Hydra-Slide, was onsite to provide training for Yu Sin personnel on the set-up and operation of the HT300 skidding system and witness the first slide of the boring machine components.
He explained that despite the complexities involved with transporting the skidding equipment by Air to Singapore, no complications arose from utilizing the equipment underground.
This is actually the perfect application for the HT system due to its modular design, light weight and ease of assembly. No extra ground testing was necessary as the bottom of the launch shaft was poured concrete that was capable of supporting the weight of the HT300 and loads. This was the first time our equipment was used to move a TBM [tunnel boring machine] and we see future potential in this area, especially after the success of this project.
In addition to the standard HT300 skid system, Hydra-Slide’s scope of supply included provision of specially designed skid shoe extensions, which allowed the boring machine’s base full contact support with the skid system.
Jefferson Yee, general manager at Yu Sin, said the front body assembly consisted of six pieces weighing 241 tons in total, which were lowered into the launch shaft and assembled on the HT300 skid system.
The cutter head being lowered onto the assembly cradle.
It comprised the front body bottom (34 tons), bearing (98 tons), front body top (32 tons), cutter head (64 ton), working deck and man lock, which together added another 13 tons of weight.
Yee explained that after the front body was slid into place, the middle body was lowered in one 128-ton piece, followed by the 64 ton rear body and, finally, the two-part screw conveyor that weighed 28 tons. At the end of each slide, the sub-assemblies were pulled onto the launch cradle using hydraulic jacks and connected together.
The project is scheduled for completion in 2018.